Busway stab contact



July 11, 1957 ERICSQN 3,331,949

BUSWAY STAB CONTACT Filed May 25, 1964 /N VENTOR.

United States Patent 3,331,049 BUSWAY STAB CONTACT Eric A. Ericson, Plainville, Conn., assignor to General Eiectric Company, a corporation of New York Filed May 25, 1964, Ser. No. 369,738 2 Claims. (Cl. 339-252) This invention relates to contacts, more particularly to stab contacts and it has for an object the provision of a simple, reliable and inexpensive contact of this character.

More specifically, the invention relates to a male stab contact for use with apparatus in which contact engagement with a conductor or bus bar must be made by insertion into a rectangular slot or continuous opening in a busbar and a more specific object of the invention is the provision of a male stab contact of improved construction which is readily inserted and Withdrawn relative to a busbar and which effects tight engagement with a busbar when in contact therewith.

A still more specific object of the invention is the provision of a male stab contact in which a resilient mov- :able contact tab, punched from the stationary body portion of the stab but remaining integrally attached thereto, will, in response to the moderate force developed during the stab-in operation, reenter the opening from which it was punched.

In carrying the invention into effect in one form thereof, a male stab contact is formed 'by punching from a planar body portion of electroconductive material, a movable resilient tab. The tab has a base which joins the body along a base line, a tip and two sides that converge from the ends of the base line to the tip to impart a generally tapering configuration. The tab is severed from the body portion along the sides and tip and a portion of the tab is offset in a plane parallel to the plane of the body portion. The tab is so formed that in its unstressed state, the projection of the converging sides and tip on the plane of the body portion is separated from the corresponding sides and tip of the opening. A force no greater than the bare force required to flex the tab about its base line is all that is required to cause the tab to reenter the opening.

For a better and more complete understanding of the invention, reference should now be had to the following specification and to the accompanying drawing of which:

'FIG. 1 is a front view of a stab contact embodying the invention,

FIG. 2 is a side view of the contact of FIG. 1,

FIG. 3 is a side view of a stab contact embodying the invention inserted in a longitudinal opening of .a tubular busbar,

FIGS. 4 and 5 are simple sketches of details and FIG. 6 is a simple sketch of a detail of a modification.

Referring now to the drawing and particularly to FIGS. 1, 2 and 3, the invention is illustrated .as embodied in a stab contact having a body portion 1 and a flexible movable tab 2. The body portion 1 has a generally oblong configuration with an arcuate shaped stab end. The arcuate configuration is not essential to the invention; the end edge could be rectilinear with rounded corners. The stab contact may be made of any suitable material. For example it may be made of an extra hard phosphor bronze with limited phosphorous.

The tab has a tip 2a and a base 2b joining the body portion along a base line 20 and sides 2d and 2e which converge from the ends of the base line to the tip to impart a generally tapering configuration. The tab 2 is punched from the body portion by means of a suitable punching tool (not shown). It is severed from the body portion along the converging sides 2d and 2e and tip 20 "ice but remains attached to the body portion along the base line 2c. Thus, there is formed in the body portion an opening 3 having the same configuration as that of the tab 2.

As shown in FIG. 2 the tab is bent up out of the plane of the body portion along the base line 2c, i.e., the base line is the bend line of the deformation. Along a second bend line 2f the tab is given a reverse bend so that an intermediate portion of it is ofiset from the plane of the body portion and occupies a plane parallel thereto. The tip of the tab is bent out of the plane of the offset portion of the tab and into the tip portion of the opening 3. This bend takes place along the bend line 2g.

By shaping the tab with converging sides and offsetting it from the plane of the body portion without squeezing the metal of the offset portion, the tab will be drawn down, i.e., displaced toward its base to provide clearance with respect to the body portion both at the tip and along the converging sides. For the same amount of displacement of the tab toward its base and with decreasing slope of the converging sides of the tab the clearance between the converging sides of the tab and the corresponding sides of the opening in the body portion will increase. This is illustrated in FIGS. 4 and 5. In FIG. 4 with a given displacement at of the tab toward its base and with a slope of the clearance c between the sloping sides of the tab and the corresponding sloping sides of the opening in the body portion is relatively small. In FIG. 5, for the same displacement of the tab toward its base and with a slope of 45 the clearance 0' between the sides of the tab and the corresponding sides of the opening in the body portion is relatively large. Since the clearance needed is small, the exact slope of the converging sides is not critical.

The construction illustrated in FIGS. 1, 4 and 5 is especially useful in applications in which space is severely limited such for example as in the application illustrated in FIG. 3. In this application the stab contact is stabbed into engaged with a tubular busbar 4 having a narrow longitudinal slot that is defined by the int-urned edges 4a and 4b. The width of the stab contact may be inch or less and, as illustrated in FIG. 3, the width of the slot between edges 4a and 4b may be 1 times the thickness of the stab material.

In operation, when the stab contact 1 is stabbed into a slot in a busbar, the tab 2 makes contact engagement with edge 4a of the busbar as illustrated in FIG. 3. As the stab motion progresses, a force is developed against the tab 2 which overcomes its resilience and causes it to flex about its bend line and to reenter the opening in the body portion from which it was punched. Owing to the clearance between its edges and the corresponding edges of the opening, no greater force is required to spring the tab into the opening than the bare force required to flex it about its bend line.

It is not essential to the invention that the tip of the tab 2 be relatively narrow or that it be rounded as illustrated in FIGS. 1, 4 and 5. For a relatively wide stab contact, the tip of the tab may be relatively wide also and it may have a rectilinear edge as illustrated in FIG. 6.

Although a particular embodiment of the invention has been shown and described, changes and modifications that do not depart from the invention will readily suggest themselves to persons skilled in the art. In the appended claims it is aimed to cover all such changes and modifications as fall Within the true spirit of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A stab type electrical contact constructed of a single piece of generally planar relatively thin metallic material comprising:

(a) a rigid planar body portion having a free end adapted to be inserted into a female contact;

(b) a resiliently movable tab portion comprising an intermediate generally triangular portion of said 'body portion having a base joining said body portion along a base line and a pair of sides converging from the ends of said base line to a tip portion, said tip portion being adjacent said free end, said converging tab sides and said tip being severed from said body portion and said tab being displaced out of the plane of said body portion so that said body portion has an opening conforming to the outline of said tab portion and having the same dimensions as said tab portion;

(c) said tab having a portion thereof immediately between said tab and said edges of said opening when. said tab tip is sprung into said opening; and ((1) said tab tip extending out of the plane of said major intermediate portion toward said plane of said body portion and into the tip end of said opening to permit said tab tip to be inserted into said female contact. 2. A stab type electrical contact as set forth in claim 1 wherein the surface of said intermediate portion of said tab is spaced from the corresponding surface of said body portion a distance substantially equal to the thickness of said tab portion.

References Cited UNITED STATES PATENTS 2,159,938 5/1939 Chirelstein.

2,206,662 7/1940 Conradi et al.

2,294,608 9/1942 Rudolphsen 339252 X 2,950,134 8/1960 Strange 28753 MARVIN A. CHAMPION, Primary Examiner.

PATRICK A. CLIFFORD, Examiner.

P. TEITELBAUM, Assistant Examnier. 

1. A STAB TYPE ELECTRICAL CONTACT CONSTRUCTED OF A SINGLE PIECE OF GENERALLY PLANAR RELATIVELY THIN METALLIC MATERIAL COMPRISING: (A) A RIGID PLANAR BODY PORTION HAVING A FREE END ADAPTED TO BE INSERTED INTO A FEMALE CONTACT; (B) A RESILIENTLY MOVABLE TAB PORTION COMPRISING AN INTERMEDIATE GENERALLY TRIANGULAR PORTION OF SAID BODY PORTION HAVING A BASE JOINING SAID BODY PORTION ALONG A BASE LINE AND A PAIR OF SIDES CONVERGING FROM THE ENDS OF SAID BASE LINE TO A TIP PORTION, SAID TIP PORTION BEING ADJACENT SAID FREE END, SAID CONVERGING TAB SIDES AND SAID TAP BEING SEVERED FROM SAID BODY PORTION AND SAID TAB BEING DISPLACED OUT OF THE PLANE OF SAID BODY PORTION SO THAT SAID BODY PORTION HAS AN OPENING CONFORMING TO THE OUTLINE OF SAID TAB PORTION AND HAVING THE SAME DIMENSIONS AS SAID TAB PORTION; (C) SAID TAB HAVING A PORTION THEREOF IMMEDIATELY ADJACENT SAID BASE LINE EXTENDING AT AN ANGLE TO SAID PLANE OF SAID BODY PORTION AND SAID TAB HAVING A MAJOR INTERMEDIATE PORTION THEREOF EXTENDING IN A PLANE PARALLEL TO AND SPACED FROM THE PLANE OF SAID BODY, SAID TAB BEING SLIGHTLY DISPLACED LONGITUDINALLY TOWARD SAID BASE LINE WITH RESPECT TO SAID OPENING SO THAT SAID CONVERGING EDGES OF SAID TAB SIDES AND THE EDGE OF SAID TAB TIP ARE SEPARATED FROM THE CORRESPONDING EDGES OF SAID OPENING TO PROVIDE CLEARANCE BETWEEN SAID TAB AND SAID EDGES OF SAID OPENING WHEN SAID TAB TIP IS SPRUNG INTO SAID OPENING; AND (D) SAID TAB TIP EXTENDING OUT OF THE PLANE OF SAID MAJOR INTERMEDIATE PORTION TOWARD SAID PLANE OF SAID BODY PORTION AND INTO THE TIP END OF SAID OPENING TO PERMIT SAID TAB TIP TO BE INSERTED INTO SAID FEMALE CONTACT. 